JP2018033090A - Transmission line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a strong transmission line in which reflection loss is low over broadband.SOLUTION: A transmission line 1 includes: a post wall waveguide 10 having a region, surrounded by first and second conductor layers 12a, 12b formed on both surfaces of a dielectric substrate 11 and a post wall 13 formed on the dielectric substrate 11, as a waveguide region; a hollow square waveguide 20 connected with the first conductor layer 12a so as to cover an opening OP formed in the sidewall, and the inside of which communicates with the waveguide region via an opening H formed in the first conductor layer 12a; a blind via-hole 30 formed in the dielectric substrate 11 so that one end is located in the opening H; and a pole member 40 having a pillar member 41 and a support member 42 for connection with the blind via-hole 30, and placed in the waveguide 20 so that the pillar member 41 is coaxial with the blind via-hole 30.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a transmission line.

  Conventionally, waveguides have been used as transmission lines for transmitting high-frequency signals from the microwave band (0.3 to 30 [GHz]) to the millimeter wave band (30 to 300 [GHz]). In recent years, a post-wall waveguide (PWW) is also used as a transmission line for transmitting such a high-frequency signal. The post-wall waveguide is formed by a pair of conductor layers formed on both surfaces of the dielectric substrate and a pair of post walls formed by arranging a plurality of conductor posts formed so as to penetrate the dielectric substrate in two rows. This is a rectangular waveguide.

  The above-described waveguide and post-wall waveguide may be used alone or in combination. For example, in a communication module, a transmission line in which a waveguide and a post wall waveguide are combined is used as a transmission line between a transmission / reception circuit and an antenna. In such a communication module, for example, a high-frequency signal output from a transmission / reception circuit is transmitted to the waveguide after being transmitted by the post wall waveguide, and is transmitted from the antenna after being transmitted by the waveguide.

  The following Patent Documents 1 to 7 disclose conventional transmission lines in which different types of transmission lines are combined. For example, the following Patent Documents 1 to 5 disclose conventional transmission lines in which a waveguide and a post wall waveguide are combined. Patent Document 6 below discloses a conventional transmission line in which a waveguide and a printed board are combined. Patent Document 7 below discloses a conventional transmission line in which a microstrip line and a post wall waveguide are combined.

Japanese Patent No. 5885775 Japanese Patent Laid-Open No. 2015-80100 JP 2015-226109 A JP 2012-195757 A Japanese Patent No. 4395103 Japanese Patent No. 4767944 Japanese Patent No. 3464104

  By the way, in recent years, communication using the E band (70 to 90 [GHz] band) has attracted attention. In such communication, for example, a broadband high-frequency signal in the band of 71 to 86 [GHz] is connected to a common port (antenna connection terminal) of a diplexer (a three-port filter element that is connected to an antenna and separates two frequency bands). Are input and output. Therefore, a transmission line for transmitting such a high-frequency signal is required to have a low reflection loss over a wide band of 71 to 86 [GHz] (for example, the reflection loss is -15 [dB] or less). Is done.

  Here, for example, the transmission line (transmission line in which the waveguide and the post wall waveguide are combined) disclosed in Patent Document 1 described above has a low reflection loss band, for example, 57 to 67 [GHz] band. It is. Thus, in the transmission line disclosed in Patent Document 1 described above, the band in which the reflection loss is reduced is about 10 [GHz], and a high-frequency signal over a wide band such as the above-described 71 to 86 [GHz] band is transmitted. Has the problem of insufficient bandwidth.

  In addition, the transmission line disclosed in Patent Document 1 described above has a configuration in which a waveguide is vertically attached to a dielectric substrate that forms a post-wall waveguide so that the transmission direction of a high-frequency signal is orthogonal. Has been. For this reason, in the transmission line disclosed in Patent Document 1 described above, when an external force is applied to the waveguide, for example, a moment is generated, and a large force acts on the location where the waveguide is attached to the post wall waveguide. When the dielectric substrate forming the post wall waveguide is made of a brittle material such as glass, there is a problem in strength.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a strong transmission line with low reflection loss over a wide band.

In order to solve the above-described problems, a transmission line (1) according to the present invention includes a dielectric substrate (11) having a pair of post walls (13a, 13b) formed thereon, and a first opposing surface via the dielectric substrate. A post-wall waveguide having one conductor layer (12a) and a second conductor layer (12b) and having a waveguide region defined by the pair of post walls and the first conductor layer and the second conductor layer. (10) and the first conductor layer is connected so as to cover the opening (OP) formed in the side wall (21b), and the inside of the pipe is formed through the opening (H) formed in the first conductor layer. A hollow rectangular waveguide (20) communicating with the waveguide region, a blind via (30) formed in the dielectric substrate so that one end is disposed inside the opening, and connected to the blind via Column member (41) and a support member for supporting the column member ( It has a 2) comprises a pawl member (40) disposed in said waveguide to said post member is the blind via coaxial.
In the transmission line of the present invention, the blind via and the column member are connected by a conductive connecting member (50).
In the transmission line of the present invention, one end of the blind via is formed with a land (L1) having a diameter larger than that of the blind via and on which the conductive connection member is disposed. At one end disposed on the blind via side, a land (L2) having a diameter larger than that of the column member and on which the conductive connection member is disposed is formed.
In the transmission line of the present invention, the conductive connecting member is a spherical member having a solder layer formed on the surface thereof.
In the transmission line of the present invention, the blind via is formed along an inner wall of a hole formed from the opening side to the middle of the dielectric substrate, and has a bottomed cylindrical shape.
In addition, the transmission line of the present invention includes a plurality of bumps (BP) that support the support member at a plurality of locations on the first conductor layer.
In the transmission line of the present invention, the support member has a rectangular parallelepiped shape whose length in the direction orthogonal to the axial direction of the waveguide is shorter than the length in the axial direction of the waveguide.
In the transmission line of the present invention, the axial direction of the waveguide is the same as the direction in which the waveguide region of the post wall waveguide extends.

  According to the present invention, the post-wall waveguide and the waveguide are guided so that the inside of the waveguide and the waveguide region of the post-wall waveguide communicate with each other through the opening formed in the first conductor layer of the post-wall waveguide. A blind via having one end disposed in the opening is formed in the dielectric substrate of the post-wall waveguide, and a conductor column is coaxial with the blind via in the waveguide tube. The pole member made to become is arrange | positioned. Thereby, a strong transmission line with low reflection loss over a wide band can be obtained.

It is a perspective view which shows the principal part structure of the transmission line by one Embodiment of this invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. It is the BB line end view in FIG. It is a section arrow view expanding and showing a blind via and pole member in one embodiment of the present invention. It is sectional drawing which shows the structural example of the blind via in one Embodiment of this invention. It is a side view which shows the 1st modification of the transmission line by one Embodiment of this invention. It is an end elevation which shows the 2nd modification of the transmission line by one Embodiment of this invention. It is a figure which shows the simulation result of the electric field strength distribution of the high frequency signal transmitted with the transmission line which concerns on an Example. It is a figure which shows the simulation result of the reflection characteristic and transmission characteristic of the transmission line which concern on an Example.

  Hereinafter, a transmission line according to an embodiment of the present invention will be described in detail with reference to the drawings. In the following, for easy understanding, the positional relationship of each member will be described with reference to the XYZ orthogonal coordinate system (the position of the origin is changed as appropriate) set in the drawing as necessary. Further, in the drawings referred to below, the dimensions of each member are appropriately changed as necessary for easy understanding.

  FIG. 1 is a perspective view showing a main configuration of a transmission line according to an embodiment of the present invention. 2 is a cross-sectional view taken along line AA in FIG. 3 is an end view taken along the line BB in FIG. In these XYZ orthogonal coordinate systems in FIGS. 1 to 3, the X axis is set in the longitudinal direction (front-rear direction) of the transmission line 1, and the Y axis is set in the width direction (left-right direction) of the transmission line 1. The Z axis is set in the height direction (vertical direction) of the transmission line 1.

  As shown in FIGS. 1 to 3, the transmission line 1 includes a post wall waveguide 10, a waveguide 20, a blind via 30, and a pole member 40, and extends along the longitudinal direction (X direction) of the transmission line 1. Transmit high frequency signals. In this embodiment, in order to facilitate understanding, a case where the transmission line 1 transmits a high-frequency signal in a direction from the −X side to the + X side will be described as an example. It is also possible to transmit a high frequency signal in the direction from the + X side to the -X side. Moreover, the high frequency signal transmitted by the transmission line 1 is a high frequency signal of E band (70-90 [GHz] band), for example.

  The post wall waveguide 10 includes a dielectric substrate 11, a first conductor layer 12a, a second conductor layer 12b, and a post wall 13. The first conductor layer 12a, the second conductor layer 12b, the post wall 13, This is a waveguide having a region surrounded by a waveguide region. The dielectric substrate 11 is a flat substrate formed of a dielectric material such as glass, resin, ceramics, or a composite thereof. The first conductor layer 12a and the second conductor layer 12b are thin film layers formed on the upper surface and the bottom surface of the dielectric substrate 11 with a conductor such as a metal such as copper or aluminum, or an alloy thereof, for example. The body substrates 11 are opposed to each other. The first conductor layer 12a and the second conductor layer 12b can be connected to the outside so as to have a ground potential.

  The post wall 13 is a wall member formed by arranging a plurality of conductor posts P formed so as to penetrate the dielectric substrate 11 and connect the first conductor layer 12a and the second conductor layer 12b. It is. Here, the conductor post P is formed, for example, by performing metal plating such as copper on a hole (through hole) that penetrates the dielectric substrate 11 in the thickness direction (direction along the Z-axis). The post wall waveguide 10 can also be manufactured by processing a double-sided copper-clad laminate such as a printed circuit board (PCB).

  The post wall 13 includes a pair of first post walls 13a and 13b extending in parallel to the longitudinal direction (X direction) of the post wall waveguide 10 and a second post wall extending in the width direction (Y direction) of the post wall waveguide 10. 13c (short wall). The pair of first post walls 13a and 13b is formed by arranging a plurality of conductor posts P in two rows along the longitudinal direction with a predetermined interval in the width direction. The second post wall 13c is formed by arranging a plurality of conductor posts P in a row between the + X side ends of the pair of first post walls 13a and 13b.

  As described above, in the post wall waveguide 10, a region surrounded by the first conductor layer 12 a and the second conductor layer 12 b and the post wall 13 is a waveguide region. For this reason, the interval between the conductor posts P constituting the post wall 13 is set to an interval at which the high-frequency signal propagating in the waveguide region does not leak to the outside of the post wall waveguide 10. For example, it is desirable that the interval (distance between the centers) of the conductor posts P adjacent to each other is set to be not more than twice the diameter of the conductor posts P.

  Here, in the first conductor layer 12a constituting a part of the post wall waveguide 10, for example, an opening H having a circular shape in plan view is formed. Note that the shape of the opening H in plan view may be a shape other than a circular shape (for example, a rectangular shape). The opening H is formed at a position between the pair of first post walls 13a and 13b and separated from the second post wall 13c by a predetermined distance on the −X side. The opening H is preferably formed at a position where the distance from each of the pair of first post walls 13a and 13b in the width direction is equal.

  The waveguide 20 is a hollow rectangular member including a pair of upper and lower wide walls 21a and 21b, a pair of left and right narrow walls 21c and 21d, and a narrow wall 21e at one end (the end on the −X side). The waveguide 20 has a wide wall 21b cut out at one end thereof, and an opening OP (see FIGS. 2 and 3) is formed in the wide wall 21b. For example, the wide wall 21b is cut out with a width approximately equal to the width of the post-wall waveguide 10 at the center in the width direction, and at least the opening H and the pole formed in the first conductor layer 12a in the longitudinal direction. The member 40 is cut out by a length that can be accommodated in the tube, and is cut out in the vertical direction so that at least the inside of the waveguide 20 is exposed to the outside.

  The waveguide 20 covers the opening OP formed in the wide wall 21b, and the axial direction of the waveguide 20 and the direction in which the waveguide region of the post wall waveguide 10 extends are the same direction. The first conductor layer 12a of the post wall waveguide 10 is connected. As a result, the waveguide 20 extends in the same direction (X direction) as the direction in which the waveguide region of the post wall waveguide 10 extends, and the post wall waveguide 10 passes through the opening H formed in the first conductor layer 12a. It is in a state of communicating with the waveguide region.

  Specifically, as shown in FIG. 2, the post wall waveguide 10 has an end portion (an end portion close to the second post wall 13c) in contact with the wide wall 21b, and the first conductor layer 12a is an inner wall of the wide wall 21b. Are attached to the waveguide 20 so as to be flush with each other. As shown in FIGS. 2 and 3, the first conductor layer 12a of the post-wall waveguide 10 has three openings H that are formed by a pair of left and right narrow walls 21c and 21d of the waveguide 20 and a narrow wall 21e at one end. It is soldered to the narrow walls 21c, 21d, 21e so as to be surrounded.

  As shown in FIG. 3, the width of the waveguide 20 in the tube is set to be slightly wider than the distance between the pair of first post walls 13a and 13b. The height of the waveguide 20 in the tube is as shown in FIG. 3, the height of the pole member 40 is set higher than the height of the pole member 40 (precisely, the height including the conductive connecting member 50). As described above, since the narrow wall 21e is soldered to the first conductor layer 12a, the inside of the waveguide 20 extends in the + X direction from the narrow wall 21e. The width and height of the waveguide 20 in the tube are appropriately set according to the characteristics of the transmission line 1.

  The blind via 30 is a via extending in the up-down direction and formed so that one end is disposed inside the opening H and the other end is disposed inside the dielectric substrate 11. The blind via 30 is preferably formed so that one end is arranged in the center of the opening H. The length of the blind via 30 is strictly set to a predetermined length. FIG. 4 is an enlarged cross-sectional view of the blind via and the pole member according to the embodiment of the present invention. FIG. 4 is an enlarged view of a part of FIG.

  As shown in FIG. 4, a land L <b> 1 having a larger diameter than the blind via 30 is formed at one end of the blind via 30. A conductive connection member 50 used for connecting the pole member 40 is disposed on the land L1. The land L <b> 1 is provided in order to increase the contact area with the conductive connection member 50 and increase the connection strength with the pole member 40. The blind via 30 and the land L1 described above are formed by applying metal plating such as copper, for example, in the same manner as the conductor post P formed on the post wall waveguide 10, for example. An antipad AP having a circular ring shape is formed between the land L1 and the first conductor layer 12a.

  FIG. 5 is a cross-sectional view showing a configuration example of a blind via according to an embodiment of the present invention. As shown in FIG. 5A, the blind via 30 is a member having a bottomed cylindrical shape that is formed along the inner wall of a hole 11a formed from the opening H side to the middle of the dielectric substrate 11, for example. Alternatively, the blind via 30 is a cylindrical member formed so as to fill a hole 11a formed from the opening H side to the middle of the dielectric substrate 11, for example, as shown in FIG.

  The blind via 30 is formed together with the land L1 regardless of the configuration shown in FIGS. In addition, the blind via 30 is formed after a base layer (a base layer formed of titanium, tungsten, or the like) is formed on the inner wall of the hole 11a regardless of the configuration shown in FIGS. 5 (a) and 5 (b). However, in FIG. 5A and FIG. 5B, illustration of the underlayer is omitted. The shape of the blind via 30 may be a shape (for example, a rectangular tube shape or a rectangular column shape) other than a bottomed cylindrical shape (or a columnar shape).

  The pole member 40 is a rectangular parallelepiped member including a conductor column 41 (column member) and a support member 42, and is disposed in the waveguide 20 so that the conductor column 41 is coaxial with the blind via 30. The conductor column 41 is a cylindrical or cylindrical member that is made of, for example, a metal such as copper or aluminum, or an alloy thereof, and has the same diameter (or the same diameter) as the blind via 30. The conductive via member 50 is connected to the blind via 30. The length of the conductor column 41 is set to a strictly predetermined length, like the blind via 30. The shape of the conductor column 41 may be a columnar shape or a shape other than a cylindrical shape (for example, a rectangular column shape or a rectangular tube shape).

  As shown in FIG. 4, a land L <b> 2 having a larger diameter than the conductor column 41 is formed at one end of the conductor column 41 (one end disposed on the blind via 30 side). A conductive connection member 50 used for connection to the blind via 30 is disposed at the bottom of the land L2. The land L2 has the same diameter (or the same diameter) as the land L1, and is provided to increase the contact area with the conductive connection member 50 and increase the connection strength with the blind via 30.

  The support member 42 is a rectangular parallelepiped member formed of glass, resin, or the like, and supports the conductor column 41 and facilitates mounting of the conductor column 41 (mounting on the post wall waveguide 10). Provided. The above-described conductor column 41 is embedded in the support member 42 so as to pass through the center (center of gravity) of the support member 42, for example. The conductor column 41 is entirely embedded in the support member 42 except for the end where the land L2 is formed. That is, the support member 42 is provided so as to surround the conductor column 41 except for the end portion where the land L2 of the conductor column 41 is formed.

  Here, it is desirable that the length of the support member 42 in the width direction is shorter than the length in the longitudinal direction. This is due to the following reason. That is, the high-frequency signal propagating through the tube of the waveguide 20 propagates in the longitudinal direction (the axial direction of the waveguide 20) while being reflected by the pair of left and right narrow walls 21c and 21d of the waveguide 20. Since the wavelength of the high-frequency signal is shorter when propagating through the support member 42 than when propagating through the waveguide 20, if the length of the support member 42 in the width direction is long, an extra phase is required. Rotation can cause adverse effects. In order to minimize such extra phase rotation as much as possible, it is desirable that the support member 42 has a shorter length in the width direction than a length in the longitudinal direction.

  The conductive connection member 50 is a member used for connecting the blind via 30 and the conductor column 41 of the pole member 40. Specifically, the conductive connection member 50 is used to electrically connect the blind via 30 and the conductor column 41 and to fix one end of the blind via 30 and one end of the conductor column 41. As the conductive connection member 50, for example, a conductive adhesive such as solder or silver paste, a spherical member (for example, a copper spherical member) having a solder layer formed on the surface, or the like can be used.

  Here, in the case of the blind via 30 having the configuration shown in FIG. 5A, if, for example, solder is used as the conductive connection member 50, solder melted by heating flows into the blind via 30, resulting in poor connection. It is possible that this will occur. Therefore, in the case of the blind via 30 configured as shown in FIG. 5A, it is desirable to use the spherical member having a diameter larger than the inner diameter of the blind via 30. If such a connecting member is used, the spherical member is soldered to one end of the blind via 30 by the solder formed on the surface of the spherical member while the spherical member remains at one end (upper end) of the blind via 30. The above-mentioned connection failure is prevented.

  In the transmission line 1 having the above configuration, the high-frequency signal guided from the −X side to the post wall waveguide 10 is surrounded by the first conductor layer 12 a and the second conductor layer 12 b of the post wall waveguide 10 and the post wall 13. Is propagated in the direction from the −X side to the + X side. When the high-frequency signal propagating through the waveguide region of the post wall waveguide 10 reaches the position where the blind via 30 is formed, the high-frequency signal is guided through the blind via 30 and the pole member 40 connected by the conductive connecting member 50. Guided into 20 tubes. The high frequency signal guided to the pole member 40 is radiated into the tube of the waveguide 20 from the conductor column 41 arranged in a protruding state in the tube of the waveguide 20, and the inside of the tube of the waveguide 20 from the −X side. Propagates toward the + X side.

  As described above, in the present embodiment, the inside of the waveguide 20 and the waveguide region of the post wall waveguide 10 communicate with each other through the opening H formed in the first conductor layer 12a of the post wall waveguide 10. Thus, the post wall waveguide 10 and the waveguide 20 are connected. The dielectric substrate 11 of the post-wall waveguide 10 is formed with a blind via 30 having one end disposed inside the opening H. The conductor pillar 41 and the support member 42 are provided in the tube of the waveguide 20. The pole member 40 is disposed so that the conductor pillar 41 is coaxial with the blind via 30.

  Here, the blind via 30 formed in the dielectric substrate 11 has a function of once releasing the mode of the high-frequency signal propagating through the waveguide region of the post wall waveguide 10 and then guiding it to the outside of the post wall waveguide 10. It is thought to be responsible. Further, the conductor column 41 arranged in a protruding state in the tube of the waveguide 20 forms a mode in the waveguide 20 of the high-frequency signal guided to the outside of the post wall waveguide 10 by the blind via 30. It is thought that it has a function as a starting point. With these functions, in this embodiment, it is considered that the reflection loss can be reduced over a wide band.

  In the present embodiment, the first conductor layer 12a of the post wall waveguide 10 and the waveguide are guided so that the axial direction of the waveguide 20 and the direction in which the waveguide region of the post wall waveguide 10 extends are the same. The tube 20 is connected. For this reason, for example, if the bottoms of the post wall waveguide 10 and the waveguide 20 are supported, the conventional configuration (a configuration in which the waveguide is vertically attached to the dielectric substrate forming the post wall waveguide). ).

  As mentioned above, although embodiment of this invention was described, this invention is not restrict | limited to the said embodiment, It can change freely within the scope of the present invention. For example, the following first to fourth modifications can be considered.

<First Modification>
FIG. 6 is a side view showing a first modification of the transmission line according to the embodiment of the present invention. In FIG. 6, the same members as those shown in FIG. 4 are denoted by the same reference numerals. In the above-described embodiment, the pole member 40 is configured to be supported only by the conductive connection member 50 on the post wall waveguide 10. However, the pole member 40 may be supported at a plurality of locations on the post wall waveguide 10 as shown in FIG.

  As shown in FIG. 6, in this modification, lands L <b> 20 are formed at the four corners of the bottom of the support member 42 that forms part of the pole member 40. The land L20 is formed by applying metal plating such as copper, for example, and is a member having a circular shape in plan view, for example. Note that the shape of the land L20 in plan view may be a shape other than a circular shape (for example, a square shape).

  Further, four lands L10 are formed on the post wall waveguide 10. These lands L10 are formed at positions facing each of the lands L20 in a state where the pole member 40 is disposed on the post wall waveguide 10 so that the conductor column 41 is coaxial with the blind via 30. The land L10 is formed of the same material as the land L20, for example, and is a member having the same shape as the land L20. The land L10 may be formed of a material different from that of the land L20, or may have a shape different from that of the land L20.

  Bumps BP are respectively provided between the opposing lands L10 and L20. The bump BP is a spherical member that supports the bottom of the pole member 40 on the post wall waveguide 10. As the bump BP, for example, a spherical solder (so-called solder ball), or a spherical member having a solder layer formed on the surface thereof, like the conductive connecting member 50, can be used. Note that the shape of the bump BP may be other than a spherical shape.

  In the pole member 40 shown in FIG. 6, the conductor column 41 is formed so as to extend from the bottom surface to the top surface of the support member 42, and the land L <b> 3 having a larger diameter than the conductor column 41 is formed on the top surface of the support member 42. Is formed. The land L3 is formed of the same material as the land L2 formed on the bottom surface of the support member 42, and is a member having the same shape as the land L2. The land L3 may be formed of a material different from that of the land L2, or may have a shape different from that of the land L2. Further, the land L3 may be omitted.

  As described above, in this modification, the pole member 40 is supported by the conductive connection member 50 and the plurality of bumps BP on the post wall waveguide 10. For this reason, the pole member 40 can be supported more stably and firmly on the post wall waveguide 10 than in the embodiment described above.

<Second modification>
FIG. 7 is an end view showing a second modification of the transmission line according to the embodiment of the present invention. In the embodiment described above, the width of the waveguide 20 is set wider than the width of the post-wall waveguide 10 (see FIG. 3). However, as shown in FIG. The width of the waveguide 10 may be the same (or substantially the same). 7 and 3 are compared, in this modification, the thickness of the pair of left and right narrow walls 21c and 21d of the waveguide 20 is reduced, and the width of the waveguide 20 and the width of the post wall waveguide 10 are reduced. Are the same. Note that the width of the waveguide 20 can be set to be narrower than the width of the post wall waveguide 10 if the high-frequency signal propagating in the waveguide 20 does not leak to the outside.

<Third Modification>
In the transmission line 1 described in the above-described embodiment, the direction in which the waveguide region of the post wall waveguide 10 extends and the axial direction of the waveguide 20 are the same direction. However, the direction in which the waveguide region of the post wall waveguide 10 extends and the axial direction of the waveguide 20 may intersect (for example, orthogonal) in plan view. If the bottom portions of the post wall waveguide 10 and the waveguide 20 are supported, the direction in which the waveguide region of the post wall waveguide 10 extends and the axial direction of the waveguide 20 intersect in plan view. Similarly to the above-described embodiment (a configuration in which the direction in which the waveguide region of the post wall waveguide 10 extends and the axial direction of the waveguide 20 are the same direction), it can be made stronger than the conventional configuration.

<Fourth modification>
Further, in the above-described embodiment, the case where the support member 42 forming a part of the pole member 40 disposed in the tube of the waveguide 20 has a rectangular parallelepiped shape has been described as an example. However, the support member 42 is not limited to a rectangular parallelepiped shape, and may have another shape (for example, a spherical shape).

  The inventor of the present application actually designed and simulated the transmission line having the above-described configuration, and obtained the intensity distribution of the high-frequency signal transmitted through the transmission line, and the reflection characteristic and transmission characteristic of the transmission line. The design parameters of the transmission line 1 for which the simulation was performed are as follows.

Post wall waveguide 10
Thickness of the dielectric substrate 11: 520 [μm]
Dielectric constant of dielectric substrate 11: 3.82
Interval between first post walls 13a and 13b (center-to-center distance): 1540 [μm]
Distance (distance between centers) between second post wall 13c and blind via 30: 480 [μm]
Diameter of opening H (antipad AP): 340 [μm]
-Waveguide 20
Height in tube: 1149 [μm]
Width in tube: 2500 [μm]
Distance from the center of the conductor column 41 to the narrow wall 21e: 985 [μm]

・ Blind via 30
Diameter: 100 [μm]
Length: 420 [μm]
Land L1 diameter: 200 [μm]
・ Pole member 40
Longitudinal length: 1000 [μm]
Width: 970 [μm]
Height: 700 [μm]
Diameter of the conductor column 41: 100 [μm]
Land L2 diameter: 200 [μm]
-Conductive connection member 50
Height: 100 [μm]

  FIG. 8 is a diagram illustrating a simulation result of the electric field strength distribution of the high-frequency signal transmitted through the transmission line according to the example. The simulation result shown in FIG. 8 is for a case where a high-frequency signal having a certain frequency (for example, 80 [GHz]) is transmitted from the right side of the drawing to the post wall waveguide 10 and transmitted in the left direction of the drawing. The high-frequency signal guided to the post wall waveguide 10 is transmitted to the left side of the paper through the waveguide 20 after being guided to the waveguide 20.

  Referring to FIG. 8, in the right side portion of the post wall waveguide 10 in the drawing, the electric field strength of the high-frequency signal changes in a stripe shape in the direction from the right side of the drawing to the left side of the drawing (transmission direction). Thus, it can be seen that the high-frequency signal guided to the post wall waveguide 10 is transmitted in the transmission direction in a certain mode inside the post wall waveguide 10. Similarly, in the left side portion of the waveguide 20 on the paper surface, the electric field strength of the high-frequency signal changes in a striped pattern in the transmission direction. Thereby, it can be seen that the high-frequency signal guided into the tube of the waveguide 20 is transmitted in the transmission direction in a certain mode through the tube of the waveguide 20.

  Further, referring to FIG. 8, the electric field strength of the high-frequency signal does not change in a stripe shape at the position where the blind via 30 of the post wall waveguide 10 is provided, and the electric field strength of the high-frequency signal is It is remarkably strengthened between the other end and the bottom surface of the post wall waveguide 10 (second conductor layer 12b). Such an electric field strength is considered to be obtained by once releasing the mode of the high-frequency signal propagating through the waveguide region of the post wall waveguide 10 by the blind via 30.

  Referring to FIG. 8, the charge intensity of the high frequency signal is remarkably increased between the pole member 40 and the post wall waveguide 10. Specifically, the charge intensity of the high-frequency signal is remarkably increased in the portion above the portion where the circular ring-shaped antipad AP is formed (see FIG. 4). By obtaining such electric field strength, it is considered that the mode is formed starting from the conductor column 41 provided on the pole member 40.

  FIG. 9 is a diagram illustrating simulation results of reflection characteristics and transmission characteristics of the transmission line according to the example. In FIG. 9, the curve with the symbol R is a curve indicating the reflection characteristic of the transmission line, and the curve with the symbol T is a curve indicating the transmission characteristic of the transmission line. Referring to the curve R in FIG. 9, the band where the S parameter is −15 [dB] or less (the band where the reflection loss is low) is about 73 to 90 [GHz]. As described above, the transmission line according to the present embodiment has low reflection loss over a wide band, and can transmit, for example, a high-frequency signal in the E band (70 to 90 [GHz] band) with low loss. I understood.

DESCRIPTION OF SYMBOLS 1 ... Transmission line, 10 ... Post wall waveguide, 11 ... Dielectric board | substrate, 12a ... 1st conductor layer, 12b ... 2nd conductor layer, 13a, 13b ... 1st post wall, 20 ... Waveguide, 21b ... Wide Wall, 30 ... Blind via, 40 ... Pole member, 41 ... Conductor post, 42 ... Support member, 50 ... Conductive connecting member, BP ... Bump, H ... Opening, L1, L2 ... Land, OP ... Opening

Claims (8)

A dielectric substrate having a pair of post walls, and a first conductor layer and a second conductor layer facing each other with the dielectric substrate interposed therebetween, wherein the pair of post walls, the first conductor layer, and the first conductor layer; A post-wall waveguide having a region surrounded by two conductor layers as a waveguide region;
A hollow rectangular waveguide connected to the first conductor layer so as to cover an opening formed in the side wall, and the inside of the tube communicating with the waveguide region through an opening formed in the first conductor layer; ,
A blind via formed in the dielectric substrate such that one end is disposed inside the opening;
A pole member connected to the blind via, and a support member that supports the pillar member, and a pole member disposed in the waveguide so that the pillar member is coaxial with the blind via;
A transmission line comprising:   The transmission line according to claim 1, wherein the blind via and the pillar member are connected by a conductive connection member. One end of the blind via is larger in diameter than the blind via, and a land on which the conductive connecting member is disposed is formed.
One end disposed on the blind via side of the column member is formed with a land that is larger in diameter than the column member and on which the conductive connection member is disposed.
The transmission line according to claim 2.   The transmission line according to claim 2 or 3, wherein the conductive connecting member is a spherical member having a solder layer formed on a surface thereof.   The said blind via is formed along the inner wall of the hole formed from the said opening side to the middle of the said dielectric substrate, and has a bottomed cylindrical shape, It is any one of Claims 1-4. Transmission line.   The transmission line according to any one of claims 1 to 5, further comprising a plurality of bumps for supporting the support member at a plurality of locations on the first conductor layer.   The length of the said supporting member in the direction orthogonal to the axial direction of the said waveguide is a rectangular parallelepiped shape shorter than the length in the axial direction of the said waveguide. A transmission line as described in 1.   The transmission line according to any one of claims 1 to 7, wherein an axial direction of the waveguide is the same direction as a direction in which the waveguide region of the post wall waveguide extends.

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